Fire-alarm device



.Nov. 18, 1930. H. MICHELMAN FIRE ALARM DEVICE Filed April 9. 1928 11v VENTOR Hl flcizelman 9- & W M

A TTORNE Y Patented Nov. 18, 1930 uurro stare-,

HARRY MICHELMAN, F BROOKLYN, NEW YORK FIRE-ALARM DEVICE Application filed April 9,

The main object of this invention is to provide a fire alarm which is actuated by a rising temperature and closes an electrical circuit to give an audible or visible alarm at one or more points distant from the seat of the trouble.

Another object of this invention is to provide a fire alarm which uses mercury or some other chemical agent, sensitive to heat, which closes a circuit to give an audible alarm, or energizes a filament alarm for a visible alarm at one or more Joints distant, to inclicate that fire exists where the instrument is mounted.

The above and other objects will become apparent in the description below, in which characters of reference refer to li e-named parts in the drawing.

Referring briefly to the drawing, Figure 1 is a longitudinal sectional clevational view of the fire alarm device showing the circuit open.

Figure 2 is an exterior front elevational view of the device.

Figure 3 is a top plan view of Figure 1.

Figure 4 is a cross sectional View through the reservoir, taken on line l i of Figure 1.

Referring in detail to the drawing, the numeral indicates a cylinder formed of transparent, nonconducting glass in which a circular well 11 is formed. The lower end or the cylinder communicates with the reservoir 12, which is itormed by providing a spherical wall 13 at the lower extremity of the cylinder 10. The upper end of the cylinder is open and is encircled by an external flange 14 which seats on the face of a recess portion of a plate 15. This plate is some what elongated in shape and is adapted to be suspended from brackets of any type, not shown on the drawing, which brackets are adapted to conveniently mount the device at any and all desirable positions. The plate 15 has a cap 16 seated thereon which captures the flange 14 within the recess and prevents the same from being displaced. At one end of the cap 16 a layer of insulation 17 rests. Seated upon this layer of insulation is a bus bar 18. This bus bar 18, the insulation layer 17, the cap 16 and the plate 15 are retained 1928. Serial no. 268,488.

and coupled together as a unit by a bolt 19 which passes through all of these members at one end of the device. Diametrically opposite a similar bolt 20 passes through the cap 16 and plate 15, bolting these two members together and, at the same time, positions terminal tongues which will be more fully hereinafter described. Seated upon the sur face of the cap 16 is a terminal tongue 21 while resting upon the bottom of the plate 15 is a bentterminal tongue 22. Both of these tongues are retained in their desired positions by the bolt 20 as is indicated in F igure 1. The bottom 19 secures a third terminal tongue 23 in place, seated upon the surface of the cap, as is indicated in Figure 1. A lead wire 24 connects the tongue 21 with the tongue 28. Connected in series to this lead wire is a source of energy 25 and a bell or buzzer 26 so that when the circuit is closed through the device the bell or buzzer will be energized and will thereby give an audible signal. The bus bar 18 has a stud 27 rising therefrom which has mounted rigidly thereon an arm 28. One end of the arm 28 is slotted as indicated by the numeral 29 in order to receive a spindle 30 which latter s rigidly fastened to the arm. The lower end of the spindle 30 terminates within the well 11 and at its lower terminating end is provided with a flange-31. The range has vents 32 formed therein, as is indicated in Figure 1. The tongue 22 has a lead wire 34 extending therefrom which depends from said tongue and, at its lower end, is connected to a needle 35. The needle pierces the wall 13 of the reservoir 12 and projects into its chamber.

The device is adapted to close an electrical circuit upon the application of heat to the liquid contents 33 of the glass container. This liquid may be mercury or some other desirable fluid which will increase its volume through the application of heat. It is wellknown that mercury, when subjected to a rising temperature, will increase its volume. At normal temperature the upper level of the mercury remains in a position as indicated in Figure 1. As the temperature of this mercury or other liquid rises, its volume increases and its level rises until such time as it comes in contact With the flange 31. Immediately after it contacts with this flange a circuit is closed through the flange 31, stem 30, arm 38, stud 27, busbar 18, tongue 23 through the source of energy and through the lead Wire 24 to the bell or buzzer 26 completing the circuit through the'tongue 21 bolt 20,

tongue 22, lead Wire 3% and the needle 35. As the temperature in the room or chamber'in Which the device is mounted rises to a still greater temperature the liquid contained in the Well and reservoir circulates through the vents 32 and rises above the'flange, the air being urged out through an opening in the cap 16, through which the stem passes. t will be noted that this device is extremely sensitive to ten'iperature changes and when a room in Which the device is located has a fire therein the temperature 1S necessarily ralsed and the device is set into operation notlfying the operator that something is Wrong at a particular locality in the building. r

I It is to be noted that certain changes in 7 form and construction may be made Without departing from the spirit and scope of the invention. 1

I claim: p A fire alarm device for closing an electrical i circuit and ringinga bell upon the rising of temperature comprising a Well, a reservoir communicating With said Well, a liquid in said Well and reservoir adapt-ed to increase its volume upon rise of temperature or" the surrounding atmosphere, a perforated flange, a stem suspending said flange, a tapering needle piercing the Wall of said reservoir and entering into said reservoir forming one terminal of the circuit, a bifurcated arm engaging said stem, a stud, said arm projecting from said stud, saidstem entering into said bifurcated end of said arm, and a bus bar forming a current-carrying member having said stud secured thereon. f

In testimony whereof I afiix my signature HARRY MI SHELF 1A1? 

